The present invention relates to solid waste treatment systems. More specifically, it relates to compact treatment systems which may be used in commercial transportation vehicles such as trains, ships, buses, and airplanes.
The commercial transportation industry, specifically trains, marine vessels, and airplanes, has had limited options for handling the waste generated from on-board restroom facilities. In the past, the waste from trains was simply dumped on the tracks. On ships, the waste was dumped overboard. As environmental pressures have increased, the practice of dumping has become undesirable and often illegal. In most cases, the solution has been to store the waste on-board until it can be pumped out. This method is undesirable for a number of reasons. First, the storage of waste requires space that could otherwise be used for passengers or cargo. Second, the waste is heavy and represents an additional load the vehicle must carry which reduces the total load the vehicle can carry and negatively impacts fuel economy. Third, the infrastructure is frequently not in place to handle the pumping and treatment of the stored waste. Fourth, the time it takes to pump the waste adds to the layover time adversely effecting the service time. Fifth, the stored waste is a source of odor and a potential health hazard in the event of a spill. And finally, the cost and inconvenience of storage and pumping frequently leads to illegal dumping of the waste.
The present invention relates to waste processing systems which are of a size and general configuration that permits their use on board a transport, such as a train, bus, airplane, recreational vehicle, boat, or other such moving vehicle or device. The system purifies the waste sufficiently to allow discharge, thus eliminating the storage and pump-out requirements. The liquid waste is evaporated and condensed as primarily water vapor. The resulting liquid can be safely discharged virtually anywhere. If desired, the liquid can be reused for non-potable applications. The solid waste is converted to inert ash or carbon and is either stored in a filter or discharged as carbon or ash into the water, air or onto the railroad tracks or ground.
Waste processing or treatment systems according to preferred embodiments of the present invention may also be used in stationary or semi-stationary applications where on-site treatment of waste may be desired, such as portable toilets, temporary shelters or dwellings, campsites, and the like.
In accordance with one embodiment of the present invention there is provided a system for treating waste having liquids and solids therein. The system comprises a thermal processor adapted to thermally decompose the waste into vapor and carbonaceous material and a vapor treatment system in fluid communication with the thermal processor, wherein the vapor is separated into aqueous and gaseous components and treated for disposal or reuse. In preferred embodiments, the waste treatment system further comprises a toilet waste storage tank, and the vapor treatment system comprises one or more of the following: a condenser, a disinfection module, a catalytic converter, and a flush water storage tank.
In accordance with another embodiment of the present invention, there is provided a method for treating human waste containing both solids and liquids. The method comprises thermally decomposing the waste to form carbonaceous material and vapor, treating the vapor with a catalytic converter, separating the vapor to aqueous and gaseous components, exhausting the gaseous components, and treating the aqueous components. In accordance with preferred embodiments, the method further comprises disinfecting the aqueous components and recycling the disinfected aqueous components for re-use within the system, or disinfecting the aqueous components and releasing the treated aqueous components outside the system. In preferred embodiments, the separating comprises condensation and/or the treating comprises passing the gaseous components through a catalytic converter to oxidize ammonium or nitrogen-containing compounds in the vapor.